高产几丁质酶菌株的诱变选育及发酵条件的优化

Yield improvement in a chitinase-producing strain by mutation breeding and optimization of fermentation conditions

以粘质沙雷氏菌G3-1为出发菌株,通过紫外-Li Cl和微波-Li Cl两轮复合诱变,得到一株产酶能力高且遗传稳定的突变株GF-21,通过单因素实验和正交实验对突变株GF-21的发酵培养基和发酵条件进行优化。结果表明,最优发酵培养基成分为:乳糖6 g/L,尿素10 g/L,KCl 1.0 mmol/L,Na Cl 5 g/L,胶体几丁质10 g/L,此时,几丁质酶活力为4.73 U/m L,比优化前提高了109.3%,较出发菌株提高了470%;最优发酵条件为:培养基初始p H9.0,温度30℃,摇床转速220 r/min,接种龄5 h,接种量10%。本文为几丁质酶的生产应用奠定了良好的基础。

A mutant strain GF-21with high yield and stable inheritance was obtained by double round mutagenesis of ultraviolet -LiCl and microwave-LiCl using Serratia marcescens G3-1 as original strain. The fermentation conditions of GF-21 were investigated using single factor and orthogonal experiment.The result showed that the optimal fermentation medium contained 6 g/L lactose,10 g/L urea, 1.0 mmol/L KCl and 5 g/L NaCl,10 g/L colloidal chitin.Under the optimal fermentation medium condition,the ehitinase activity was 4.73 U/mL which was 1.09-fold higher than that before optimization and was 4.7-fold higher than original strain.The optimal fermentation conditions were as follows： the initial pH9.0, the temperature 30 ℃, the shaking speed 220 r/min, the inoculation age 5 h, the inoeulum size 10%.The result provided a theoretical foundation for chitinase applications.